Weather Briefing — La Rochelle → Gibraltar

Issued from 18 Aug 2026 ~17Z data. Advisory only — verify underway.

Current synoptic setup

The route is dominated by a broad Azores High (~1025 hPa) centred near 35°N 25°W (Chart 1), ridging NE toward Biscay with 1020 hPa over the western approaches. A shallow 1010 hPa low sits over the North Sea/southern Norway, dragging a weak trough across the British Isles — this is the only meaningful disturbance near the route. A deeper 1000 hPa low south of Iceland with a sharp 552 dam 500 hPa trough (Chart 1) is the upstream player. Over Iberia and the approaches to Gibraltar, gradients are slack (1015–1020 hPa). Chart 4 confirms: 20–26 kt WSW over the western Channel/NW Biscay, 8–14 kt over southern Biscay and off Portugal, light and variable near Gibraltar. Satellite (Chart 8) shows the frontal cloud band draped across the UK, well north of the route.

72-hour outlook

• Day 1 (Tue→Wed, La Rochelle → mid-Biscay): WSW–W 15–22 kt across northern Biscay, easing to W–NW 10–15 kt by 46°N. Seas 2–2.5 m from NW (Chart 7, 24 hr). No frontal passage on the route; front stays over UK.
• Day 2 (Thu, mid-Biscay → Finisterre): Ridge builds — Chart 2 shows 1025 hPa nosing over Biscay. Winds back to N–NW 10–18 kt, occasional 20 kt off Finisterre as the corner accelerates. Waves 1.5–2 m NW (Chart 6). Portuguese trades (Nortada) filling in south of Finisterre.
• Day 3 (Fri→Sat, off Portugal → Cape St Vincent): Chart 3 shows a new 1000 hPa low SW of Iceland at 96 hr but the Azores ridge (1030 hPa) holds firm over Iberia. Expect N–NNE 15–22 kt off Portugal (classic Nortada), waves 1.5–2.5 m from N. Light and variable approaching Gibraltar Strait; watch for local Levanter/Poniente diurnal effects.

Top 3 risks to watch

• Finisterre acceleration zone. Chart 5 shows a 22–28 kt yellow tongue off NW Iberia at t+48h as the ridge tightens. Uncertain how far offshore it extends. Trigger: if 24 hr wind prog shows sustained >25 kt at 43°N 10°W, stand off further west or delay rounding.
• Downstream Icelandic low (Chart 3). By Sat the 1000 hPa low deepens SW of Iceland with a sharp 500 hPa trough. Beyond the 96 hr window it could send a front into Biscay next week. Trigger: if the 120 hr prog shifts the low south of 55°N, the tail-end front may reach Portugal — accelerate southbound.
• Nortada strength off Portugal. Chart 3 pressure gradient between Iberian thermal low and Atlantic ridge could tighten. Trigger: MSLP difference >8 hPa between Lisbon and 40°N 15°W means 25–30 kt sustained N — reef early, favour offshore track.

Routing considerations

Window is open — depart now. The setup is benign: post-frontal WSW easing to a building ridge, no organised low threatening the route inside 96 hr. Key legs:

• Cross Biscay promptly (Days 1–2) while winds are moderate WSW–NW; aim to be south of 45°N before Day 3.
• Round Finisterre with sea-room (25–40 nm offshore) to avoid the acceleration zone and cape-effect seas.
• Off Portugal, expect the Nortada — a downwind slide; keep 15–25 nm offshore to stay clear of gusty coastal band.
• Approaching Gibraltar, check Strait forecasts within 24 hr — Levanter can set up quickly regardless of synoptic pattern.

Favour the southern/western semicircle of any late-week frontal system by staying south and pressing on. Re-brief at 20 Aug 00Z GFS run before committing past Finisterre.

Weather Briefing — La Rochelle → Gibraltar

Issued from 17 Aug 2026 00Z/16Z data — advisory only, verify underway

Current synoptic setup

The North Atlantic is in a benign, ridge-dominated pattern for the route. A broad Azores High (~1025 hPa) is centred near 35°N 25°W (Chart 1), extending a ridge over Iberia and the Bay of Biscay — MSLP 1015–1020 hPa across the whole route corridor. A weak 500 hPa trough sits over the British Isles/North Sea (552 dam contour dipping to Scotland, Chart 1), driving a shallow surface low ~1000 hPa near southern Norway — well clear of us. No organised Atlantic depression is tracking toward Biscay in the 48-hr window (Chart 6). Satellite (Chart 8) confirms a cloud-free Iberia and only scattered convective cells west of Portugal. The controlling feature for the passage is thus the Azores ridge, which strengthens through midweek (1025 hPa core building north on Chart 3).

72-hour outlook

Day 1 (Mon 17 → Tue 18) — Departure from La Rochelle. Chart 4 shows NW–N 8–14 kt across Biscay, locally 15 kt offshore. Chart 7 (24-hr wave) shows seas 1–2 m across Biscay and off Finisterre. No frontal activity. Off Portugal: N 10–15 kt (Portuguese trades), seas 1.5–2 m.

Day 2 (Tue 18 → Wed 19) — Ridge builds. Chart 5 shows N–NNE 10–16 kt through Biscay, freshening to 15–20 kt off NW Iberia (Finisterre acceleration zone visible as a yellow patch, ~18–22 kt). Chart 6: seas 2–3 m west of Finisterre from northerly swell; 1–2 m elsewhere on route. No fronts.

Day 3 (Wed 19 → Thu 20) — Continued N'ly flow, 12–18 kt off Portugal, easing to NE 8–12 kt approaching Cape São Vicente and into the Gulf of Cádiz. Seas 1.5–2.5 m off Portugal, dropping <1.5 m near Gibraltar. Expect the usual Levanter risk in the Strait — not resolvable at this chart scale.

Top 3 risks to watch

• Finisterre acceleration / nortada. Chart 5 shows a distinct 18–22 kt tongue off NW Iberia at T+48. Uncertain how far offshore it extends. Trigger: sustained >20 kt with building NW swell → stand 40–60 NM offshore of Finisterre.
• Strait of Gibraltar Levanter (E'ly gale). Not visible on these synoptic charts; the pressure gradient across Iberia (Chart 3, 1015 Atlantic vs 1010 W Med) is weak but could tighten. Trigger: Tarifa/Gibraltar showing E >25 kt on arrival day → hold at Barbate or Cádiz.
• Longer-range trough (Chart 3, T+96). A 1015 hPa low drifts SE toward the British Isles by Fri 21 Aug, trailing a front toward Biscay. Timing/southward extent uncertain. Trigger: front dropping south of 48°N in updated 00Z runs → push through Biscay early rather than delay.

Routing considerations

Window is OPEN — depart now. The Azores ridge gives 3+ days of favourable N–NE quadrant winds down the whole route. Prioritise clearing Biscay in the first 48 hours before the Day-4 trough matters. Give Finisterre a 40 NM offing to stay outside the acceleration/swell peak. Once past Cape São Vicente, monitor Tarifa actuals 12 hrs before Strait entry — favour a W-going tide with W'ly or light winds; avoid Levanter-against-tide. If the Day-4 trough deepens in later runs, you'll want to be south of 43°N by Wed 00Z — achievable at 6+ kt SOG from La Rochelle.

Weather Briefing — La Rochelle → Gibraltar

Snapshot: Sun 16 Aug 2026 16:49 UTC

Current synoptic setup

The eastern North Atlantic is in a slack, weakly-gradient pattern. Chart 1 shows the Azores High displaced south/southwest with a 1025 hPa ridge centred near 40°N 30°W, extending a weak nose over Iberia (1015–1020 hPa). A shallow 1010 hPa low sits over the British Isles / western approaches, with a trough sagging into Biscay — this is the feature governing Day 1 winds on the route. Chart 7 confirms a broad 588–594 dam upper ridge over the subtropical Atlantic with the jet well north (564 dam near 55°N), so no organised deep lows are being steered onto the route. Satellite (Chart 8) shows only benign cumulus streets over Biscay and clear skies over Iberia/Gibraltar approaches — no frontal cloud band threatening the corridor.

72-hour outlook

Day 1 (Mon 17 Aug): Chart 6 (24 hr) shows Biscay winds W–NW 10–15 kt, seas 1–2 m (a 2 m patch near 45°N 10°W). Off Finisterre, N–NNE 10–15 kt, seas 1–2 m. Portuguese coast: N 10–15 kt (nascent Portuguese trade). Gulf of Cádiz / Gibraltar approaches: light, variable <10 kt, seas <1 m. No frontal passage.

Day 2 (Tue 18 Aug): Chart 4 shows Biscay backing/veering NW 12–18 kt, locally 20 kt on the Spanish shelf. Chart 5 gives seas 2 m in Biscay, 2–3 m in the pocket W of Finisterre. Portuguese coast N 15–20 kt (nortada firming). Strait approaches remain light E–SE 8–12 kt; watch for a Levanter signature building in the Alborán.

Day 3 (Wed 19 Aug): Extrapolating Charts 2 & 7: ridge rebuilds over Iberia (1020 hPa), Biscay eases to W 10 kt / 1–1.5 m. Portuguese coast N 15–20 kt persistent. Gibraltar: E 15–25 kt Levanter possible in the Strait itself.

Top 3 risks to watch

• Portuguese nortada acceleration off Finisterre & C. Roca — Chart 4 hints at a 20 kt tongue; compression against the coast can push 25–30 kt with 3 m seas. Trigger to reroute offshore: sustained >22 kt at Cabo da Roca buoy.
• Levanter in the Strait — Charts 1/2 show a weak E–W pressure gradient across Gibraltar building by Day 3. Charts don't resolve Strait-scale acceleration. Trigger: Tarifa reporting >20 kt E — delay Strait entry or stage at Barbate.
• Biscay trough deepening — Chart 2 (96 hr) shows the UK low still near 1010 hPa; any southward slip brings SW 25 kt onto Day 4. Trigger: 96 hr prog showing <1005 hPa centre south of 50°N — depart sooner or shelter.

Routing considerations

Window is OPEN now — depart within 24 hr to cross Biscay before Day 2's NW freshening. Aim to be south of 44°N by Tue 00Z. Off Portugal, hold 30–50 nm offshore to skirt the nortada compression zone. Favour the southern/right semicircle of the Biscay trough (winds behind you). Time Strait entry with the westbound tidal stream and before any Levanter fills — target a dawn Gibraltar approach.

Advisory only — verify with GRIB updates and coastal VHF forecasts underway.

Weather Briefing — La Rochelle → Gibraltar

Snapshot: Sat 15 Aug 2026 16:49Z

Current synoptic setup

The route is under the eastern flank of a broad Azores High, with the 1025 hPa ridge centred near 35°N 30°W (Chart 1) extending a 1020 hPa tongue across Biscay and Iberia. No organised low threatens the track: the nearest active system is a 1005 hPa low south of Iceland with an associated trough draped SW–NE across 55°N, well north of the route. At 500 hPa, a deep -30°C cold pool sits over Greenland/Iceland with the 552 dam contour bulging south to ~58°N — the jet stays north of Biscay, so the route is in slack, warm, subsident flow. Chart 4 confirms light-to-moderate N–NE'lies (8–14 kt) down Biscay and along the Portuguese coast, with the Nortada already established (14–18 kt off Finisterre). Chart 7 shows mostly clear skies over Iberia and the eastern Atlantic — a benign starting picture.

72-hour outlook

Day 1 (Sun 16 Aug) — Biscay crossing. N–NNW 10–15 kt across central Biscay, backing NW near Finisterre. Seas 1–2 m from the NW (Chart 6, 24 hr). No fronts on the route. Clear to fair.

Day 2 (Mon 17 Aug) — Finisterre to Lisbon. Ridge builds (1025 hPa nosing into Biscay per Chart 2). Portuguese trades N–NE 15–20 kt, locally 20–22 kt in the Finisterre/Nazaré acceleration zone. Wind waves 1.5–2 m, low NW swell ~2 m (Chart 5 shows 2 m offshore Portugal). Downwind sailing, but lumpy near capes.

Day 3 (Tue 18 Aug) — São Vicente to Gibraltar. N 12–18 kt off Cape São Vicente easing to NE 10–15 kt in the Gulf of Cádiz. Seas 1–1.5 m. Approaching Gibraltar, expect the usual Strait effect — likely Levanter (E 20–30 kt) setting up as pressure gradient tightens between Iberian ridge (1020) and Alboran (1015, Chart 3).

Top 3 risks to watch

• Levanter in the Strait. Chart 3 shows a 5 hPa gradient across Gibraltar by Tue. Uncertainty: timing and strength. Trigger to change plan: Tarifa observations >25 kt E — hold at Barbate or Cádiz.
• Finisterre acceleration. Chart 4 already shows 18+ kt patches off NW Iberia; the ridge build (Chart 2) tightens the gradient. Uncertainty: exact isobar spacing. Trigger: if Finisterre buoy reports >25 kt sustained, stand offshore 30+ NM to soften seas over the shelf edge.
• North Atlantic low tracking east. Chart 3 hints at a 1005 hPa low near 55°N 20°W by Day 4 — outside window but the associated NW swell could reach Biscay/Iberia. Trigger: if 96 hr progs deepen it below 1000 hPa or shift south, expect swell 3 m+ off Portugal by Day 5.

Routing considerations

Window is open — depart now. The setup is textbook for a downhill run: ridge stays put through Day 3, no fronts cross the route, and the Portuguese trades are working with you. Push south steadily; don't dawdle in Biscay as the ridge amplification behind you (Chart 3) will strengthen N'lies late in the week. Time Finisterre for early morning to avoid the afternoon sea-breeze boost. Stay 20–30 NM offshore along Portugal to keep clear of cape acceleration and fishing gear. At Gibraltar, plan the Strait entry on a westbound tide with light Levanter — if E winds exceed 25 kt, wait at Barbate. Favour the southern/eastern side of any Atlantic low you see developing on updated progs (safe semicircle for a southbound track).

Advisory only — verify against GRIBs, Navtex, and OPC updates underway.

Weather Briefing — La Rochelle → Gibraltar

Issued: 14 Aug 2026 17:30 UTC · Advisory only — verify underway

Current synoptic setup

The route is dominated by a broad Azores High ridging at 1025 hPa west of Iberia and extending into the Bay of Biscay at ~1020 hPa (Chart 1). No organised low threatens the route: the nearest disturbance is a weak 1015 hPa feature over the central North Atlantic near 50°N 25°W, and a deeper 1005 hPa low is far north over the Norwegian Sea — well clear. At 500 hPa the ridge axis (568–572 gpdm) sits over Iberia/Biscay, giving a stable, blocked pattern. Satellite (Chart 7) confirms mostly clear skies over Biscay and the Iberian approaches, with only shallow stratocumulus offshore Portugal. The pattern drifts slowly east through the period; the 96 hr prog (Chart 3) shows the ridge holding, with a weak 1005 hPa low approaching SW Ireland — a signal to watch, not yet a threat to the route.

72-hour outlook

Day 1 (Sat 15 Aug) — Biscay crossing

Chart 6 (24 hr): winds NW–N 10–15 kt across Biscay, easing to 5–10 kt near the Spanish shelf. Seas 1–2 m from the NW. No fronts. Fair sailing but light on the southern half.

Day 2 (Sun 16 Aug) — Finisterre to off Lisbon

Charts 2, 4, 5: Portuguese trade corridor activating — N–NNE 15–22 kt off the Portuguese coast (the yellow patch on Chart 4 near 40°N/10°W indicates ~20–25 kt "nortada"). Seas 2–3 m N-NW, locally 3.5 m west of Portugal (Chart 5). Fast reach south; watch acceleration off Cabo da Roca.

Day 3 (Mon 17 Aug) — São Vicente to Gibraltar

Chart 3: ridge still in place, 1020 hPa over Iberia. Expect N 15–20 kt to Cape São Vicente, then E–ENE 10–18 kt Levanter building in the Gulf of Cádiz and Strait approaches. No frontal passage.

Top 3 risks to watch

• Nortada acceleration off Portugal. Chart 4 shows 20–25 kt band; compression against the coast can push gusts 30+ kt with steep seas. Uncertain how far offshore it extends. Trigger: buoy or QuikSCAT winds >25 kt sustained at 40°N/10°W — stand further offshore (>40 nm).
• Levanter in the Strait. Chart 3 suggests light gradient, but Alboran pressure gradient can spike quickly. Trigger: Gibraltar/Tarifa METAR showing E >20 kt or Ceuta–Málaga ΔP >4 hPa — delay Strait transit or pre-stage at Barbate.
• Atlantic low approaching Ireland by Day 4+. Chart 3 hints at a 1005 hPa system near SW Ireland at t+96 h. Not on the route yet, but any faster tracking would lift southerly swell into Biscay. Trigger: ECMWF/GFS shifting the low south of 50°N — accelerate the Biscay leg.

Routing considerations

Departure window is OPEN — leave within 24 h. The ridge is stable through Day 3 and offers a classic downhill run: NW in Biscay, N off Iberia, easterly finish. Prioritise clearing Finisterre by end of Day 2 to ride the nortada rather than fight a strengthening one. Stand 30–50 nm offshore of Portugal to avoid coastal gust compression. Time the Strait entry for slack/westbound tide and before any Levanter build — aim for a morning arrival at Tarifa. If the Day 4 Irish low deepens on later runs, favour the western/leading edge by pressing south rather than loitering in Biscay.

Weather Briefing — La Rochelle → Gibraltar

Issued: Thu 13 Aug 2026 17:30 UTC · Advisory only — verify against fresher data underway.

Current synoptic setup

The North Atlantic is in a benign, ridge-dominated pattern for mid-August. Chart 1 shows a broad Azores High near 1025 hPa centred west of the Iberian Peninsula, with its ridge extending NE across Biscay (1020 hPa isobar draped over the route). No organised low pressure threatens the corridor between 34–50°N / 15°W–3°E; the nearest activity is a weak 1015 hPa trough well NW of Ireland and the climatological Icelandic low near 1005 hPa. At 500 hPa (Chart 1), the 564–568 dam contours lie flat over Iberia — no sharp shortwave troughs digging south. Chart 4 confirms light-to-moderate N–NE flow of 8–16 kt down the Portuguese coast (Portuguese trades / Nortada) and 6–12 kt over Biscay. Chart 8 (satellite) shows mostly clear skies over Biscay and Iberia, cellular stratocumulus offshore — classic subsidence under the high.

72-hour outlook

Day 1 (Fri 14 Aug) — Biscay leg. N to NNW 10–16 kt, backing NW inshore. Seas 1.5–2 m from NW (Chart 7, 24 hr wave). No fronts. Visibility good; some morning stratus possible near Finisterre.

Day 2 (Sat 15 Aug) — Finisterre → Lisbon. Chart 2 shows the Azores ridge holding at 1025 hPa, ridge axis over the route. Chart 5: N–NE 12–20 kt along the Portuguese coast (Nortada strengthens), lighter 8–12 kt offshore. Chart 6: seas 2 m NW off Portugal, dropping to 0.5–1 m in the Gulf of Cádiz. Note the 3.5 m swell isolated pocket off NW Iberia (~9°W/40°N) on Chart 6 — a residual NW swell worth watching.

Day 3 (Sun 16 Aug) — São Vicente → Gibraltar. Chart 3 (96 hr) shows the ridge weakening slightly as an Atlantic trough digs SE of Greenland, but Iberia stays under 1015–1020 hPa. Expect N 10–15 kt rounding São Vicente, then E–ENE 12–18 kt (Levanter) building in the Strait approach. Seas 0.5–1 m.

Top 3 risks to watch

• Nortada acceleration off Portugal. Chart 5 hints at 18–20 kt along the coast; compression against the Portuguese shelf can push this to 25+ kt in afternoons. Trigger: pressure gradient tightening between Azores High and Iberian thermal low → route 30–50 NM offshore.
• Levanter in the Strait of Gibraltar. Not visible on these charts at synoptic scale, but Day 3 easterly flow suggests build-up. Trigger: Gibraltar METAR showing E 20+ kt, or MSLP gradient Cádiz–Málaga >4 hPa → time Strait entry for slack or west-going tide.
• Residual NW swell off Finisterre. Chart 6's 3.5 m pocket at ~9°W. Uncertain whether it decays or persists. Trigger: buoy 62081 (Silleiro) reporting >2.5 m at 10+ s → stand further offshore or delay 12 hr.

Routing considerations

Window is OPEN — depart now. The Azores ridge gives 3–4 days of favouring quarter-to-following N–NE winds Biscay through Iberia. Cross Biscay directly (avoid a slow ride under the ridge axis if you dally). At Finisterre, stand 20–30 NM off to skirt the swell pocket and Nortada acceleration zone. Round São Vicente by Sunday midday to reach Gibraltar before any Levanter reinforces mid-week. Favour the western/southern semicircle of the Azores High — you already are — keeping the high to port for sustained N'lies.